I had been using astrid for a long time, but soon I realized I wanted to be able to write my to dos on my comp and have it sync. Astrid syncs with Remember the Milk, but you have to pay for RTM. Instead I found the app Got To Do. It is based on the GTD workflow and is an amazing app. Its like astrid on steroids, but it takes up less space. Many options and many ways to sort. Not to mention you can have notes on each individual task you add. The app syncs with Toodledo.com which is a great site, very easy to use, and free. There is a paid version of the app, but all that allows you to do is to add subtasks to tasks. A feature I don't really need, but trust me, the lite version is robust enough. Seriously, if you like having a to do list or want to organize yourself, really check this app out. Its been doing wonders for me. Forgot to mention it also has a widget (just like astrids, only white)